A casting method of casting a plurality of cast-metal objects simultaneously by one casting operation is widely used. In a general casting method, cavity portions for casting a plurality of cast-metal products and a runner portion for supplying molten metal to each of the cavity portions are formed continuously in one mold structure as a casting frame or mold. By using this casting device, molten metal is supplied from the runner portion to the plurality of cavity portions.
As such a method of casting a plurality of cast-metal objects simultaneously, there are a gravity casting mold and a mold casting structure (Patent Document 1). A tree-like wax model for lost wax casting is known (Patent Document 2). A die casting method and device are known (Patent Document 3). Even a low-pressure casting method may cast a plurality of cast-metal objects by one casting operation.